Oxidizing and optical bleach



jaJQ HLE LitLi'i -Jg OXIDIZING AND OPTICAL BLEACH Caroline Butler, SouthPlainfield, NJ., assignor to American Cyanamid Company, New York, N.Y.,a corporation of Maine No Drawing. Application April 27, 1954 Serial No.426,052

3 Claims. (Cl. 252-99) The present invention is concerned with thebleaching of fibrous materials. Still more particularly, it is concernedwith bleaching compositions for whitening natural protein and syntheticfibrous materials. Still more particularly, it is concerned withperborate bleaching compositions having incorporated therein an organicfluorescent compound as an optical bleaching agent.

It is well known that white textile materials such as silk, wool, nylonand the like tend to develop a yellowish cast over a period of time,particularly after repeated washing and/ or exposure to sunlight. Tocounteract this color deterioration, it is customary to add to detergentcompositions used for laundering such fibrous materials any of varioustypes of bleaching compositions. Such bleaching compositions compriseany of variously known oxidizing compounds. One such type of bleachingcomposition which has found wide use in both commercial and domesticlaundering practice contains sodium perborate as the oxidizing agent.Admixed with the perborate may be various compounds such as trisodiumphosphate, sodium tripolyphosphate, sodium sulphate, sodium chloride,sodium carbonate and the like, each of which exerts certain beneficialeffects on the bleaching bath. Although the oxidizing agent of suchcompositions bleaches or whitens the treated material, the whitening eflect obtained is limited and in many instances is not sufiicient torestore the original brightness and white appearance of the material.

It has also been proposed to eliminate the yellowish cast of suchtextile materials by the use of certain classes of organic substanceswhich can be applied from solution to the material and which, byfluorescing blue thereon in daylight, appear to restore the originalwhite color. It has also been proposed to combine such organicfluorescent materials with chemical bleaching agents so as to obtain thecombined elfect of chemical bleaching and optical bleaching. To be soemployed, however, an organic fluorescent material must be compatiblewith the alkaline bleach composition.

One of the most useful fluorescent organic compounds for whiteningnatural protein and synthetic fibrous materials is4-methyl-7-diethylaminocoumarin. This compound, however, is notresistant to the action of sodium perborate and/or the other alkaliingredients found in a conventional perborate bleaching composition.Soon after mixing of this compound with the perborate bleachcomposition, a very objectionable odor develops and becomesprogressively worse on standing or on exposure to elevated temperatures.This in itself is suflicient to make the composition completelyunsalable.

There has remained, therefore, a demand for bleaching compositionscomprising both a chemical bleaching agent and an optical bleachingagent for use in both commercial and domestic laundering of naturalprotein and synthetic fibrous materials. Such a bleaching compositionshould be stable and not develop objectionable odors during extendedperiods of storage or on exposure to elevated temperatures. It shouldprovide a whitening 2,903,430 Patented Sept. 8, 1959 and brighteningefiect to the treated material which is superior to the effect obtainedby either alone. Such a composition, moreover, should be capable ofproviding this whitening and brightening effect to various syntheticfibrous materials such as nylon and the like without danger of physicaldamage.

It is therefore the primary object of the present invention to provide anew bleaching composition meeting this demand. This object has beenfulfilled to a surprisingly successful degree. It has now been foundthat a bleaching composition comprislng a perborate bleachingcomposition as a chemical bleach and 4-methyl-7-dimethylaminw coumarinovercomes to a striking degree the various drawbacks noted above withrespect to previous chemical bleaching compositions having incorporatedtherein an organic fluorescent compound.

What is completely unexpected in view of the past history of the use ofthe diethyl homologue of the optical bleach of this composition is thecomplete stability of the composition of this invention during periodsof extended storage or on exposure to elevated temperatures. Whereas aperborate composition comprising 4-methyl-7-diethylaminocoumarindevelops an objectionable odor after mixing, the composition of thisinvention is surprisingly free of odor. Nor does the optical bleach ofthis composition tend to lose its brightening effect as do the diethylhomologue and other various coumarin derivatives.

The amount of 4-methyl-7-dimethylaminocoumarin employed may be quitewidely varied. In general, however, as little as 0.01% by weight of theperborate component will provide an effective Whitening of the materialtreated. While as much as 2% of the fluorescent organic compound may beemployed, such large amounts are usually unnecessary and provide littleif any additional brightening eliect. In most cases, amounts rangingfrom about 0.01% to about 1.0% will suflice to give the maximum opticalbrightening effect.

The following examples will further demonstrate the invention. Theseexamples are intended to be illustrative only and not by way oflimitation. All parts are by weight unless otherwise noted.

Example 1 One part of 4-methyl-7-dimethylaminocoumarin and 2000 parts ofa commercial bleach containing about 30% sodium perborate, 60% sodiumsulfate and 6% Water were dry blended. The resulting composition wasplaced in an enclosed container and exposed for one week to roomtemperature. On opening the container there was no objectionable odornoted.

Example 2 The procedure of Example 1 was repeated substituting4-methyl-7-diethylaminocoumarin for the dimethyl homologue thereof.After storage for a week under similar conditions the composition had anoticeably repulsive odor.

Example 3 When the compositions of Examples 1 and 2 were sub jected tofurther storage for one week while being exposed to a temperature of 110F. the bleach composition containing the4-methyl-7-dimethyl-aminocoumarin was still free of objectionable odorwhile the odor of the composition containing the diethyl homologue hadbecome substantially more repulsive.

Example 4 A bath is prepared using one part of a perborate bleach asused in Example 1 and 400 parts "of water at F. A second bath isprepared using one part of the perborateaminocoumarin composition ofExample 1. Ten parts .The procedure of Example 4 is repeated except thenylon fabric is replaced by acetate fabric. The acetate fabric treatedin a bath according to this invention is substantially whiter whenexamined in daylight as compared to the fabric treated in a bathcontaining only the perborate bleach.

Example 6 The procedure of Example 4 is repeated replacing the nylonfabric with wool. Repeated workings in baths having a compositionaccording to this invention result in a. substantially greater whiteningeffect on the wool than when worked in the bath containing only theperborate composition.

Example 7 A composition according to Example 1 is added to water at 100F. containing a detergent and nylon garments are added and washed for 15minutes followed by rinsing and drying. The garments are substantiallywhiter and brighter than equivalent nylon washed using only thedetergent and perborate bleach.

4 What I claim is:

thetic protein fibrous material which comprises a bleaching mixturewhose only active chemical bleaching ingredient is about 30% by weightof the mixture sodium perborate, the said bleaching mixture havingadmixed therein from 0.01 to 2.0% by weight of4-methyl-7-dimethylaminocoumarin.

2. The compositions of claim 1 in which the amount of the said coumarinadmixed with said bleaching mixture is from 0.1 to 1.0%.

3. A process for whitening and brightening natural protein and syntheticfibrous materials which comprises treating said fibrous materials with asolution formed by dissolving, in about 400 parts of Water, one part ofa bleaching composition consisting essentially of a chemical bleachwhose only active chemical bleaching agent is about 30%,- by weight ofthe mixture, of sodium perborate and from about 0.01% to about 2.0% byweight, of 4-methyl-7- dimethylaminocoumarin as an optical bleach.

References Cited in the file of this patent UNITED STATES PATENTS2,610,152 Ackermann Sept. 8, 1952 2,654,713 Fleck Oct. '6, 19532,692,238 Hendrix Oct. 19, 1954 2,706,178 Young Apr. 12, 1955 2,763,618Hendrix Sept. 18, 1956 2,791,564 Fleck May 7, 1957 FOREIGN PATENTS496,903 Belgium Nov. 3, 1950

1. A BLEACHING POWDER FOR WHITENING NATURAL AND SYNTHETIC PROTEINFIBROUS MATERIAL WHICH COMPRISES A BLEACHING MIXTURE WHOSE ONLY ACTIVECHEMICAL BLEACHING INGREDIENT IS ABOUT 30% BY WEIGHT OF THE MIXTURESODIUM PERBORATE, THE SAID BLEACHING MIXTURE HAVING ADMIXED THEREIN FROM0.01 TO 2.0% BY WEIGHT OF 4-METHYL-7-DIMETHYLAMINOCOURMARIN.